1. Field of the Invention
This invention concerns a bacteriocidal and fungicidal solution containing an inorganic silver complex which is effective for bacteriocidal and fungicidal use with all articles such as daily necessaries and industrial products, as well as a production process therefor.
2. The Prior Art
Recently, various products containing bacteriocidal and fungicidal agents, including sanitary porcelains as well as daily necessaries such as stationaries, have been provided. Such products are imparted with bacteriocidal and fungicidal ability by kneading water soluble organic bacteriocides or less soluble compounds of metals such as silver having a bacteriocidal effect into the materials used to make the products, or by fixing them on the surfaces of the products.
However, even such products having bacteriocidal and fungicidal agents previously used for bacteriocidal and fungicidal treatment involve a drawback of reduced bacteriocidal and fungicidal activity when the surfaces of the products are covered with stains or when silver is sulfurized when silver compounds are used as the bacteriocidal and fungicidal agents.
Further, since bacteriocidal and fungicidal agents used for the bacteriocidal and the fungicidal agent-incorporated products are in the form of powdery or like other solid form, they have to be fixed previously on the surfaces of the products by kneading or special treatment.
Therefore, the solid state bacteriocidal and fungicidal agents have a disadvantage that they can not be used by a method such as spraying on the surfaces of usual articles which are being used, for example, in homes in a case where it is intended to subsequently impart the bacteriocidal and fungicidal ability to the articles.
While on the other hand, liquid or water soluble bacteriocidal and fungicidal agents are also used although the application use is restricted. Among them, bacteriocidal and fungicidal agents of alcohols, phenols such as cresol, quaternary ammonium salts or silver complex salts comprising metals having sterilizing effect such as silver and amino acid, thiosulfate or thiocyanate have been put to practical use, and addition of bacteriocidal and fungicidal agents comprising silver thiosulfate to water in a vase has been adopted, for example, for keeping cut flowers long.
The existent liquid or water soluble bacteriocidal and fungicidal agents have an advantage capable of subsequently imparting the bacteriocidal and fungicidal ability by merely applying them on the surfaces of usual articles which are being used. However, as a problem in common with such bacteriocidal and fungicidal agents, there has been a significant drawback that they are leached out almost substantially upon water washing even when applied to the surfaces of articles, to easily lose the effect.
Moreover, the alcoholic or phenolic bacteriocidal and fungicidal agents are effective only temporarily because of their volatility and easy oxidizability and, particularly, there is a problem in view of safety that the alcoholic agents are highly flashing and phenolic agents give toxicity and keen stimulative odors. Further, the quaternary ammonium salt type bacteriocidal and fungicidal agents involve a drawback that they react with daily used anionic surfactants such as soaps or detergents, to easily loss sterilizing ability.
Furthermore, in a case of the bacteriocidal and fungicidal agents of silver complex salt type, since complex salts of silver with thiosulfate or thiocyanate contain S2xe2x88x92 ions, they are decomposed by acid or heat to evolve noxious gases and the effective ingredients are gradually converted to silver sulfide to loss the sterilizing ability. Further, the organic complex salts such as amino acid salts of silver have relatively low complex stability compared with other inorganic complex salts containing S2xe2x88x92 ions and, accordingly, they react with chloride ions which are usually present in ordinary circumstances tending to precipitate silver chloride and, as a result, the bacteriocidal and fungicidal effect is remarkably lowered. Further, like that the inorganic silver salts to be described later, they are sometimes blackened when deposited to skins and, in addition, they are difficult to be synthesized industrially compared with inorganic salts to require more production cost.
On the other hand, as traditional water soluble bacteriocidal and fungicidal agents, water soluble inorganic silver salts such as silver nitrate have been known. However, the silver nitrate and the like, although water soluble, have a serious problem that they cause precipitation of silver chloride in the inside of skins upon deposition on the skins which are reduced and blackened, as well as they are decomposed to be blackened while releasing silver by ultraviolet rays and difficult to be stored., so that they are scarcely used at present as bacteriocidal agents and fungicidal agents.
In view of the foregoing situations in the prior art, it is an object of this invention is to provide an bacteriocidal and fungicidal solution in liquid form which can impart bacteriocidal and fungicidal ability by subsequent application to the surfaces of usual products used in homes and the like, is not volatile and odorless or not deactivated for the effect by heat, acids, ultraviolet rays or anionic surfactants and retains its effect even by water washing, as well as a production process therefor.
The bacteriocidal and fungicidal solution according to this invention for attaining the foregoing purpose has a feature of containing silver ions of 0.05 mg/liter or more as a chloro complex salt in an aqueous solution containing ammonium chloride or a chloride of an alkali metal or alkaline earth metal as chloride ions.
Further, a process for producing a bacteriocidal and fungicidal solution according to this invention has a feature of preparing an aqueous solution containing ammonium chloride, or a chloride of an alkali metal or alkaline earth metal as chloride ions, adding a silver salt or metallic silver to the aqueous solution and dissolving silver ions of 0.05 mg/liter or more as a chloro complex salt.
Further, the bacteriocidal and fungicidal solution is effective both for bacteriocidal and fungicidal uses when the concentration of the silver ions contained as the chloro complex salt is 0.5 mg/liter or more but the effect is restricted to the bacteriocidal effect, since it is poor in the fungicidal effect although effective for the bacteriocidal effect at a concentration lower than the above.